SIMULTANEOUS MEASUREMENT OF ROTATIONAL AND TRANSLATIONAL DIFFUSION BYFORCED RAYLEIGH-SCATTERING - COLLOID SPHERES IN SUSPENSION

It is shown that the technique of forced Rayleigh scattering, traditio nally employed to probe translational diffusion, can be employed to pr obe rotational diffusion as well. Thus with a single experiment both q uantities are measured. The system under investigation is colloid sphe res suspended in a glass-forming liquid. Furthermore, it is shown that the Stokes-Einstein and Debye-Stokes-Einstein relations for translati onal and rotational diffusion, respectively, are valid for spherical c olloid particles in a supercooled liquid matrix in the vicinity of the glassy state.